Pulled the spare tire to clean up the trunk a bit and took a few pics. This appears to be the original spare for my 72 GS350, a General G78-14. Date code for the tire and WJ code wheel is shown in one of the pics. I was tempted to sniff some of that 72 air but thought better of it.
Brian, don't do it mon!!!!! That is sniffing air from 1972. You are only going to get your hopes up real high thinking about taking a whiff from the good 'ole days, just to get some putrid smell stuck in your nose. I actually think finding old tires is cool. My 68 GS didn't have the original spare, but close. It has 3 skinny whitewalls probably from very early 70's. I have another old spare that is a BF Goodrich G70x14. The cool part is it says Traction Advantage in white cursive lettering, and it is a "re-cap" to. Enjoy.... Stay away from the old air.